Jeffrey Lee Parson was barely 18 years old and dealing with some personal problems when he launched a variant of the Blaster worm that infected more than 48,000 computers worldwide. On Friday, a federal judge in Seattle sentenced Parson to 18 months in prison, three years of supervised release and 100 hours of community service.

"What you've done is a terrible thing. Aside from injuring people and their computers, you shook the foundation of technology," U.S. District Judge Marsha Pechman told Parsons. She will determine restitution at a hearing Feb. 10.

Parson was indicted in September 2003 and charged with sending out a variant of the MS Blaster worm on August 12, 2003.

Parson admitted he created his worm by modifying the original MS Blaster worm and adding a mechanism that allowed him to have complete access to certain infected computers, according to a statement from the U.S. Attorney's Office in Seattle, Wash.

Parson's W32.Blaster-B variant first appeared just days after W32.Blaster-A first appeared. Blaster-B used a different file name, teekids.exe, as opposed to the original msblast.exe, IDG News Service reported.

The worm was programmed to take advantage of a vulnerability in the DCOM (Distributed Component Object Model) interface component of Windows, which handles messages sent using the RPC (remote procedure call) protocol, to spread itself over the Internet and launch denial-of-service attacks against popular Web sites, including Microsoft's Windows Update Web site, the news service said.

"This defendant's malicious attack on the information superhighway caused an economic and technological disruption that was felt around the world," said Assistant Attorney General Christopher A. Wray of the Criminal Division. "Today's sentence demonstrates to criminals intent on releasing computer viruses and worms that they will be found and appropriately punished."

The judge said she took into consideration Parson's special circumstances. Parson, who weighs more than 300 pounds, was three weeks past his 18th birthday when he released the worm, had history of mental illness, and was inadequately monitored by his parents on his computer activities, the judge said.

Pechman told Parson that his community service had to be through face-to-face contact with others and restricted his use of computers to only educational and business purposes. "No video games, no chat rooms," Pechman said to Parsons. "I don't want you to have anonymous friends, I want you to have real world friends."

"An 18-month prison sentence is probably the best that Jeffrey Parson could have realistically hoped for. The U.S. authorities have demonstrated their determination to deal with virus writers and other cybercriminals," said Graham Cluley, senior technology consultant for security software company Sophos. "Parson's sentence sends out a strong message to other young people that writing vi-ruses is a fool's game. Parson and his parents will be regretting the day he decided to get involved in virus-writing.

"You can't help but feel sorry for Jeffrey Parson - he was clearly a kid with issues, who got mixed up in a game with far bigger consequences than he could have ever imagined," Cluley added. "It must not be forgotten that the identity of the author of the original Blaster worm, who infected many many more computers than Parson, is still a mystery. Despite a $250,000 bounty on their head - we are still no closer to unmasking the culprit. Jeffrey Parson is small fry when compared to the major virus-writing criminals who are still at large."